Thermal interface materials and structures have found increasing usage as the demands for thermal dissipation from heat-generating electronic devices have correspondingly increased. As electronic components used in the manufacture of various products have become both smaller in size and greater in capacity, their heat generation per unit area has increased dramatically. Because many electronic components lose efficiency and performance in elevated temperature environments, it has become imperative to utilize materials and structures proficient in removing thermal energy from and around the respective heat-generating electronic components.
In many applications, a heat diffuser, such as a heat sink or heat spreader, is employed to increase the rate at which thermal energy is removed from a heat-generating electronic component. Such heat diffusers are thermally conductive, and typically provide a heat exchange interface of relatively high capacity. For example, heat spreaders may be thermally coupled to a heat-generating electronic component and placed in the path of a moving air stream driven by a cooling fan, or may be in thermal contact with another fluid of even greater thermal capacity, such as water, in order to shed thermal energy to the thermal loading fluid. In some iterations, the heat spreaders possess relatively large surface areas to increase the potential contact area with a thermal loading fluid, as described above.
One problem that is encountered in removing thermal energy through the use of a heat dissipater is in obtaining good thermal coupling between the heat-generating electronic component and the heat dissipater. For example, respective facing surfaces of the heat-generating electronic component and the heat dissipater may be irregular, thereby preventing continuous contact therebetween. Where contact between the two facing surfaces is not obtained, heat transfer efficiency is dramatically reduced due to the fact that an additional thermal boundary in the form of a gap between the two facing surfaces is introduced, and wherein the gap likely has a lower thermal conductivity than the material of the heat dissipater.
Various solutions have been implemented in an attempt to overcome such problem, including the use of thermally conductive interface materials disposed between the heat-generating electronic component and the heat dissipater to minimize or eliminate gaps between the component and the heat dissipater. Thermal interface materials have been rendered in various forms, such as greases, waxes, pastes, gels, pads, adhesives, and the like. Conventional thermal interface materials typically contain a polymer substance that, in its bulk form, is at least somewhat conformable to a surface when placed under applied pressure and potentially within an elevated temperature environment. In some applications, such a conformable substance may be silicone oil or other polymer material. The conformability aspect of thermal interface materials is important in order to fill in any surfaces irregularities in the respective heat transfer surfaces so as to maximize the efficiency of thermal transfer from the heat-generating electronic component to the thermal interface material, and subsequently from the thermal interface material to the heat dissipater. Any gaps that may exist between the thermal interface material and the respective surfaces of the heat-generating electronic component and the heat dissipater introduce additional thermal boundaries, which reduce thermal transfer rates.
Though various thermal interface materials and structures have been developed for the purpose of removing thermal energy from heat-generating electronic components, it has been discovered that interface materials and structures may additionally be useful in acting as an electrical conductor between two bodies. Many electrically conductive connection apparati, of course, are found in the conventional arts. However, such apparatus are typically insufficiently conformable, and insufficiently thermally conductive to provide desired thermal conductivity and thermal transfer characteristics.
It is therefore a principal object of the present invention to provide an interconnect structure that is thermally and electrically conductive, and is also sufficiently conformable so as to be useful as a thermal and electrical interconnect.
It is a further object of the present invention to provide an interconnect structure that exceeds at least a minimum threshold for thermal and electrical conductivity at least along a designated direction, which direction connects a first body to a second body.
It is another object of the present invention to provide a thermally and electrically conductive interconnect structure for disposition between a first body and second body, which interconnect structure exhibits sufficient conformability so as to enable desired efficiency of thermal and electrical energy transfer between the first and second bodies.